1. Field of the Invention
The present invention relates to a cellular mobile radio network and a method for setting up a base station of a cellular mobile radio network having at least one base station, integrated in each case into a facility supplied with power via a power supply system and connected to an assigned base station controller. The at least one base station is coupled to the power supply network via first transceiver module. A second transceiver module is likewise coupled to the power supply network at another place. The transmission of electrical signals corresponding to the radio frequency signals is made possible bidirectionally between the first and second transceiver modules over the power supply network, and the second transceiver module is connected to the base station controller assigned to the at least one base station, so that a communication over the power supply network is made possible between the at least one base station and the base station controller assigned thereto. In particular the invention relates to a cellular GSM and/or UMTS mobile radio network.
2. Discussion of the Background
Modern life is hardly conceivable anymore today without data and voice communication by means of mobile radio networks. Public mobile radio networks (PLMN: Public Land Mobile Network) make it possible for users to access diverse mobile telecommunications services. Such a mobile radio network can be viewed as an extension of the public fixed network (PSTN: Public Switched Telephone Network). It is typically composed of different transmitting and receiving areas, as is described e.g. in “Digital Cellular Telecommunications System; Network Architecture: GSM (Global System for Mobile communications); Technical Specification”; European Telecommunications Standards Institute (ETSI), TS/SMG-030302Q, the entire contents of which is incorporated by reference herein. The areas are assigned to a so-called Mobile-services Switching Center (MSC), the areas having a destination code and a common routing plan. An MSC forms the functional interface between the fixed network and the mobile radio network. The MSCs provide all the necessary functions for calls to or from a mobile radio device. To obtain area coverage for the receiving and transmitting area in a particular geographic region, a multiplicity of base station systems (BSS: Base Station System) are normally necessary, i.e., each MSC is thus an interface to a multiplicity of base station systems. Moreover, a multiplicity of MSCs are usually needed to cover an entire country. A BSS is made up of a Base Station Controller (BSC) and one or more base stations (BTS: Base Transceiver Station). A base station covers a so-called receiving/transmitting cell. The base station system includes all technically necessary means (transceivers, controllers, etc.), so that the MSC is able to communicate with a particular mobile radio device in a particular cell. A BSC is a network component of the mobile radio network for activating one or more base stations.
Mobile telecommunication over such above-described public mobile radio networks has been able to show tremendous growth in all sectors in the last few years through a wide range of new and improved products both in the technological area as well as in services. That a user of such a mobile radio network would be reachable at all times and everywhere is one of the factors which have contributed to this growth. Despite great efforts, however, this aim of the industry has not been achieved everywhere owing to the high costs for installation of an area-wide network of antennas with base stations, among other things. In contrast, in centers of population concentration it is nevertheless to be observed that because of competing telecommunications companies multiple coverage of the same area can often result. An unnecessarily high exposure (electrosmog) of the population thereby results in these areas in the radio frequency range. Peak exposures in such areas can be lowered in particular by structurally related shielding being reduced or circumvented through receiving and transmitting stations of a more local nature. The search for new, cost-viable solutions with as low as possible—but still sufficient—receiving and transmitting power in this field seems more important than ever today.
The UK patent application GB 2126845 A (U.S. Pat. No. 4,777,652) discloses a method and a system for extension of mobile radio networks in closed spaces such as e.g. mines. In the system, the carrier signal is coupled or respectively modulated to existing power supply cables which supply the mine with power. Inside the mine, the signal is demodulated by a transmitting station, and is broadcast in the mine by means of a repeater. The international patent application WO 99/00906 (U.S. Pat. No. 6,151,480) shows a method and a system for transmitting radio frequency signals over a power supply network. For this purpose the frequency of the signals at a first station are converted to a second frequency, and modulated to the power supply network. A second station demodulates the signals of the power supply network, and broadcasts them in their original frequency. Finally, the U.S. patent document U.S. Pat. No. 5,832,364 discloses a system for transmitting radio frequency signals over a power supply network. As in the previously mentioned patent document, a transceiver modulates the radio frequency signals to the power supply network. A second transceiver demodulates the signals, and broadcasts them with the original frequency.
The international patent application WO 02/09462 shows a method for setting up a base station of a mobile radio network. The base stations 20/21 in FIG. 2 are thereby installed in existing facilities on exposed public ground, which facilities are supplied with power via a power supply network 21. The signal transmission of the radio frequency signals takes place bidirectionally between the base station and the base station controller over the power supply network. The drawback of this state of the art, however, is that such facilities, in particular street illumination devices, are normally activated in a time-limited way. For example, for economic (energy-saving) or environmental reasons, street illumination devices 11 as shown in FIG. 1 are often switched on only at night or when poor visibility (dusk, fog) exists, by a control module 14. Therefore, if these public facilities are not operated in an ongoing manner, no mobile radio networks can be operated during the non-activated time using such base stations of the state of the art.
In the German unexamined patent publication DE 44 21 307 (WO 95/35618), a remote control system for electrical devices is described, a radio transmitter/receiver with a remote control interface and a remote control device allocated to the electrical device being provided. By means of a control device installed on the radio transmitter, remote control commands are generated and are transmitted to the remote control device. The remote control configuration relates in particular to a DECT wireless telephone (DECT: Digital European Cordless Telecommunication) and a base station. Remote control electrical devices include, for example, consumer devices in the home or garden. It is foreseen the transmission of remote control commands to the remote control device over a participant distribution facility by means of DTMF sequences (DTMF: Dual Tone Multi Frequency), as with the remote control inquiry of a telephone answering machine.